Telemetry system

ABSTRACT

In a remote monitoring system, a supervision terminal,  37 , monitors the status of the communication link,  32, 34, 36 , between the supervision terminal and each of a plurality of remote terminals,  33 , connected to the supervision terminal via a data network,  35 . The remote terminals may be used to emulate a line interface for monitor devices such as fire alarms,  31 , while providing continual assurance of the integrity of the link between the supervision terminal and the alarm.

TECHNICAL FIELD

This invention relates to telemetry systems and will be described in thecontext of security systems such as burglar alarm systems. Inparticular, the invention provides a system which can be interposedbetween existing installed telemetry equipment such as alarm panels andtheir associated monitoring centres.

BACKGROUND ART

The challenge for remotely monitored alarm systems has always been toensure that the automatic alarm announcement resulting from an alarmcondition is correctly received at the monitoring site, being a securitycompany or the like, or in some instances, the alarm can be announced tolocal security authorities such as the police.

At their most basic form, burglar alarm systems provide an automatictelephone calling system over the normal wired telephone land lineservice to announce alarm conditions at a monitored site.

This system has a number of inherent disadvantages in that,

-   1) A burglar can cut the land line and subsequently deactivate the    alarm system and thereby gain entry to premises without being    detected-   2) Faults in the telephone network may prevent the announcement from    being received at the monitoring site-   3) At the time the burglar alarm system uses the telephone land line    to make an automated announcement the telephone land line is not    available for others to make, say an emergency telephone call-   4) As burglar alarm systems can not be uniquely identified by their    own address (see U.S. Pat. No. 6,381,307 Sur-Gard Security Systems    Ltd) it is a simple matter to have an unauthorised burglar system    masquerading as the authorised one thereby defeating the security    system

In another known system (see U.S. Pat. No. 5,131,019, VerSuS Technology,Inc.), it has been proposed to additionally provide a cellular telephoneor like radio communication device which can be activated to announce aburglar entry to the premises protected by the alarm if the telephoneland line is cut.

This system has a number of inherent disadvantages in that,

-   1) Faults in the telephone network may prevent the announcement from    being received at the monitoring site-   2) An announcement is only sent to the monitoring site infrequently    allowing the system to be disabled unbeknown to the security    company, for example by a disgruntled employee-   3) As burglar alarm systems can not be uniquely identified by their    own address (see U.S. Pat. No. 6,381,307 Sur-Gard Security Systems    Ltd) it is a simple matter to have an unauthorised burglar system    masquerading as the authorised one thereby defeating the security    system

In another known system (derived channel monitoring system, see U.S.Pat. No. 4,442,320, Base Ten Systems, Inc.), it has been proposed tomonitor the remote alarm system and the telephone land line from thetelephone company's local exchange using specialised equipment installedand operated by the telephone company that directs alarm announcementsto security companies or the like, or in some instances, to localsecurity authorities such as the police. This system thus has a need forspecific alarm carriage equipment in the telecommunications networkwhich is used to collate the alarm information for retransmission to themonitoring station.

Such an Alarm Monitoring System is shown in FIG. 1 and comprisesspecialised alarm equipment at the remote site or customer premises,alarm scanning equipment at the local telephone exchange, centralstation equipment located at one of the telephone company's offices andspecialised equipment at the security company. One implementation ofthis type of system is given below,

-   1) The burglar alarm system or associated equipment is connected to    the telephone land line and generates a low frequency out of band    signal (low tone) that is received at the telephone company's local    exchange-   2) The Alarm Scanning Equipment located at the telephone company's    local exchange regularly polls the burglar alarm system or    associated equipment with voice frequency modem signals over the    telephone land line-   3) The absence of low frequency signal (low tone) from the burglar    alarm system or associated equipment results in the alarm scanning    equipment located at the telephone company's local exchange sending    a poll request to the burglar alarm system or associated equipment-   4) The burglar alarm system or associated equipment responds to the    poll from the alarm scanning equipment located at the telephone    company's local exchange by sending as part of the poll response    message the identification of the outstanding alarms. The message is    forwarded to the telephone company's Central Station equipment where    it is converted into an alarm announcement message which is sent to    the security company over the telephone company's data network.-   5) In the event that the alarm Scanning equipment located at the    telephone company's local exchange does not get a response to a    predetermined number of poll request messages, it informs the    Central Station equipment which generates an alarm announcement    message indicating that the monitored site is no longer accessible    for the purposes of remote monitoring. This message is sent to the    security company over the telephone company's data network.

This system has a number of inherent disadvantages in that,

-   1) It can only be used where the telephone company has deployed the    Central Station equipment and then only from specific telephone    exchanges where connection to the Alarm Scanning equipment is    available-   2) Redundant paths from the burglar alarm system are not supported.    A failure of the Alarm Monitoring system prevents the burglar alarm    system from sending any announcements to the security company.-   3) The polling process uses voice frequency signalling that    interferes with the use of data modems and faxes on the telephone    land line-   4) The low frequency out of band signal (low tone) generated by the    burglar alarm system or associated equipment is incompatible with    telecommunications equipment commonly used in the customer access    network (last mile), further limiting the application of this    technology-   5) The signals transmitted on the analogue link may be encrypted,    although in practice any such encryption may be detected and broken    over relatively short time scales. Once the code has been broken,    then an attack may be made by cutting into the line and substituting    a dummy terminal which masquerades as the real terminal. This makes    it possible to disable the security system at the customer premises    without the monitoring service being alerted.-   6) The burglar alarm system or associated equipment used for this    system implement proprietary signalling and are therefore more    expensive than standard burglar alarm systems that provide an    automatic telephone calling system over the normal wired telephone    land line service to announce alarm conditions at a monitored site-   7) This system and other similar digital embodiments require the use    of intermediate equipment (Central Station in FIG. 1) often    controlled by a third party for example the telephone company which    manipulates and relays the alarm messages to the security company-   8) In this system the alarm equipment sends an announcement only    when polled by the intermediate equipment (Central Station in FIG.    1)-   9) The message transfer time of this system is determined by the    polling rate set by Alarm Scanning equipment

In another known system (ISDN monitoring system, U.S. Pat. No.6,377,589, British Telecommunications public limited company), it hasbeen proposed to monitor the alarm system and the telephone land linefrom the telephone company's local exchange by providing the telephoneservice over an ISDN basic rate access system over the land line.

Such a system is shown in FIG. 2 and comprises specialised alarmequipment at the remote site or customer premises, ISDN Terminal Adaptorequipment, ISDN NT1 equipment, Central Station equipment located at oneof the telephone company's offices and specialised equipment at thesecurity company. One implementation of this type of system is givenbelow,

-   1) The Central Station equipment located at one of the telephone    company's offices sends regular poll request messages to the burglar    alarm system or associated equipment over the ISDN ‘D’ channel-   2) The burglar alarm system or associated equipment responds to the    poll request messages over the ISDN ‘D’ channel and in the same    message sends any pending alarm announcements to the Central Station-   3) The Central Station forwards the alarm announcements to the    security company over the telephone company's data network-   4) Redundancy is supported over the GSM network with SMS (Short    Message Service) text messages

This system has a number of inherent disadvantages in that,

-   1) It can only be used where the telephone company has deployed the    Central Station equipment-   2) SMS text messages do not have guaranteed delivery times and do    not represent a reliable form of back-up. (Fire alarms are required    to report within 15 seconds).-   3) The burglar alarm system or associated equipment used for this    system implement proprietary signalling and are therefore more    expensive than standard burglar alarm systems that provide an    automatic telephone calling system over the normal wired telephone    land line service to announce alarm conditions at a monitored site-   4) To use this system the users must replace their existing    telephone system with an ISDN based system potentially incurring    significant cost and the inconvenience of having a new telephone    number assigned-   5) This system and other similar digital embodiments require the use    of intermediate equipment (Central Station in FIG. 2) often    controlled by a third party for example the telephone company which    manipulates and relays the alarm messages to the security company-   6) In this system the alarm equipment sends an announcement only    when polled by the intermediate equipment (Central Station in FIG.    2)-   7) The message transfer time of this system is determined by the    polling rate, furthermore, multiple poll periods are required to    identify a break in the land line making this system unsuitable in    some critical applications where the line break condition needs to    be rapidly identified

Another known system has set out to use the instant messaging capabilityof wide area networks, and in particular the Internet for the carriageof alarms. Patent application WO 01/11586 A1 describes such a systemwhich uses a computer located in the customer premises to collect alarmindication from sensors connected to it, and uses the Internet and acentral web site to report alarms and heart beat messages. The centralweb site reports to a response provider that either an alarm hasoccurred in the customer premises or that the computer in the customerpremises is unreachable.

This system has a number of inherent disadvantages in that,

-   1) It uses the public Internet which is significantly less secure    than a private data network-   2) It uses a central web server which is exposed to the known denial    of service attacks that can disable the entire security system    leaving the customer premises unprotected-   3) The computer in the customer premises which is in communication    with the central web site is also used to directly acquire alarm    sensor data thereby forcing the customer or user of the system to    replace their existing alarm system-   4) The system does not provide a fall back path to be used in the    event that the connection to the Internet has been lost

U.S. Pat. No. 5,943,394 (Detection Systems Inc.) describes an alarminterface system including a dialler intercept unit which connects bothto the PSTN and a wide area computer network. This system connects tostandard alarm systems and automatically selects, based on preterminedsignals from the alarm system whether the signal is sent as is over thePSTN or is translated and sent over the wide area data network.

This system has a number of limitations, including,

-   1) The system connects to the wide area network through a local area    network, such as Ethernet. Ethernet is a shared medium and is well    known for not providing a secure link-   2) The system is vulnerable to outages of the wide area network    resulting from mains failures

In addition, all the systems described above share the limitation thatthey are not directly suitable for the carriage of video.

Various telemetry and remote premises supervision systems have beenproposed that use video cameras to detect motion. When motion isdetected via some form of image comparison a remote alarm indication isgenerated and the automatic recording of video information is triggered.Some of these systems provide remote access to the video data capturedto provide visual verification of alarms to eliminate false alarms. Onesuch scheme is described by U.S. Pat. No. 6,271,752 by LucentTechnologies Inc (US).

These systems have a number of inherent disadvantages in that,

-   1) They operate completely independently of any alarm system    currently installed in the customers premises-   2) The video information is only recorded from the instant that the    alarm condition has been identified, omitting events leading up to    the alarm condition-   3) The use of motion detection to raise alarms is susceptible to    false alarms being reported

The recent introduction of ADSL systems for broadband access has createda problem for burglar alarm systems that provide an automatic telephonecalling system over the normal wired telephone land line service toannounce alarm conditions at a monitored site. The modem used toterminate the ADSL service at the customer premises generates highfrequency voltage signals that interfere with the operation of theautomatic telephone calling system of the aforementioned burglar alarmsystems, necessitating the installation of specialised signal filters byspecialist technicians to eliminate the interference.

It is therefore an object of the present invention to mitigate one ormore of the aforementioned problems.

In particular, it is advantageous to provide a system which can beinterposed between existing alarm and monitor systems.

SUMMARY OF THE INVENTION

According to a first embodiment of the invention there is provided asystem and method including:

one or more supervision terminals;

one or more remote terminals associated with at least one of thesupervision terminals;

a data network linking the supervision terminal and the remote terminalvia an “always-on” connexion through the data network providingaccessibility between the or each remote terminal and the supervisionterminal;

wherein;

the or each supervision terminal is in communication with eachcorresponding associated remote terminal across the data network usingnetwork facilities of the data network for carriage and switching orrouting of messages;

wherein messages from the remote terminal to the supervision terminalare transmitted across the network, the message content being passedtransparently across the network between the remote terminal to thesupervision terminal;

wherein:

the supervision terminal transmits poll requests to the or each remoteterminal according to a fixed or programmable routine;

the or each remote terminal, on receiving a poll request, transmits apoll response to the supervision terminal: and

the supervision terminal monitors poll responses from the or each remoteterminal to monitor accessibility between the remote terminal orterminals and the associated supervision terminal via the “always on”connexion.

Accordingly, this system can be interposed by the alarm system operatorbetween existing installed alarm panels at customer premises and thesystem monitors at the system operators premises without the need forthe installation of additional intermediate signal handling equipment inthe telecommunications network.

According to a second embodiment, the or each remote terminalcommunicates with its associated supervision terminal or terminals usinga predetermined communication protocol.

Preferably, the communication protocol used is the TCP/IP protocolsuite.

In a further embodiment, the data network is a broadband network.

Preferably, the remote terminal is linked to the network via an ADSLlink.

Alternatively or in addition, the remote terminal is linked to thenetwork via a wireless link

Preferably, the wireless link is a cellular network link.

In a further preferred arrangement, the wireless link is a GPRS link.

In a further embodiment, the supervision terminal is adapted to transmitpoll requests to the or each remote terminal, and the or each remoteterminal is adapted to transmit a poll response to the supervisionterminal on reception of a poll request.

In a further refinement, the supervision terminal transmits pollrequests at a poll request repetition rate, and wherein, when no pollresponse is received from the remote terminal within a first windowperiod in response to a poll request, the supervision terminal transmitsrepeat poll requests after the first window period, the first windowperiod being less than the poll request repetition period. Missing apredetermined number of poll responses generates alarms to the monitorsystem within the poll repetition period alleviating the need to waitfor multiple poll periods to ascertain that the remote terminal is notresponding.

Optionally, the request poll includes selectable data, and the remoteterminal includes response selection means to select a releted responsemessage from the selectable information in the poll request. To ensuresecurity, the supervision terminal includes verification means to verifythe releted response message from the remote terminal. The supervisionterminal uses the poll response from the remote terminal to verifyintegrity of the path between the remote terminal and the supervisionterminal.

Preferably, the remote terminal is adapted to transmit alarm messagesindependently of the reception of a polling request from a supervisionterminal.

In another modification, the remote terminal is adapted to transmitheartbeats to the or each associated supervision terminal. The remoteterminal may transmit heartbeats to the or each associated supervisionterminal autonomously or as a response to a poll request from anassociated supervision terminal.

In a further modification, the remote terminal includes a bypass switch;and remote terminal monitor means monitoring the remote terminal, theremote terminal monitor means being adapted to operate the bypass switchto disconnect the remote terminal and to connect the alarm terminal to atelephone network in the event of a failure of the remote terminal.

Preferably, the remote terminal includes a telemetry interface adaptedto emulate a network interface for the corresponding telemetry equipmentand to convert information received from the telemetry equipment to thenetwork communication protocol.

In an embodiment of the system, the supervision terminal is connected toan associated monitor system, which makes information received from thesupervision terminal available to an operator.

The supervision terminal preferably includes monitor interface emulationmeans converting information from the supervision terminal to themonitor information format.

The supervision terminal preferably includes supervision terminalself-diagnostic means and sends supervision terminal status reports tothe associated monitoring system. Similarly, the remote terminalincludes remote terminal self-diagnostic means and sends remote terminalstatus reports to the associated monitoring system.

To facilitate the process of associating remote terminals to supervisionterminals, an association register recording the association betweenremote terminals and supervision terminals may be provided.

An additional supervision terminal may be provided for each system toprovide redundancy.

The association register may be located in a registration server, andthe address of the registration server installed in remote terminals toenable the remote terminals to communicate with the registration serverwhen the remote terminal is powered up.

Preferably, the remote terminal includes a telemetry interface and thetelemetry interface emulates a network interface for the correspondingtelemetry equipment, converts information received from the telemetryequipment to the network communication protocol, and transmits theconverted information to the supervision terminal.

The invention also encompasses a supervision terminal for use in thesystem, and a remote terminal for use in the system.

The present invention provides a monitoring system which offers improvedsecurity and greater flexibility in operation combined with lowtransmission overheads. This is achieved by utilising the broadband IPnetwork between a plurality of Customer Terminals and a plurality ofAgency Terminals, polling the Customer Terminals from the AgencyTerminals on the broadband network and using the poll response messagesto uniquely identify the Customer Terminals. The use of IP messagingmakes possible the application unique code sequences significantlyincreasing security and reducing the likelihood of unauthorised CustomerTerminal unit substitution.

Preferably links to the broadband network from the Customer Terminal areover cable-modem, LMDS, cellular telephone system such as GPRS, 1×RTT orthird generation mobile networks (3G), DSL technology for example ADSL,Frame Relay or ATM links utilising point to point radio (such asmicrowave systems) or fibre-optic systems.

Preferably links to the broadband network from the Agency Terminal areover cable-modem, LMDS, cellular telephone system such as GPRS or 1×RTT,DSL technology, Frame Relay or ATM links utilising point to point radio(such as microwave systems) or fibre-optic systems.

A further advantage of the present invention is that it is suitable forimplementation using standard broadband access technology such as ADSLoperating on the existing telephone link. The monitoring function canthen operate transparently, without interfering with the operation ofthe telephone line. The telephone line is therefore available forsimultaneous use, for example, for voice telephony.

Preferably the Agency Terminals transmit the poll messages in onesegment and the Customer Terminals return to the Agency Terminal asingle poll response message also in one segment.

Preferably each polling request from the Agency Terminal includes anunencrypted random numerical value as well as information uniquelyidentifying the Agency Terminal and the Customer Terminal the poll isdestined for. The poll response includes an unencrypted numerical valuegenerated from a function agreed on at system initialisation used touniquely identify the Customer Terminal.

The present invention is not limited in applicability to systems inwhich the remote terminal is a burglar alarm, although the high degreeof security offered by the invention is particularly advantageous inthis context. Other uses for the invention include remote monitoring ofmeters, for example electricity, gas or water meters, or remotemonitoring of the status of an automatic vending machine.

In the description and claims the term ‘alert condition’ covers bothalarm events and poll response failures.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described with reference to the embodimentsshown in the accompanying drawings, in which:

FIG. 1 shows the typical implementation of derived channel securitysystems that use low frequency tones generated by the customer premisesequipment to provide line monitoring;

FIG. 2 shows a security network implemented over ISDN Basic ratetransmission system, where the customer's burglar alarm equipment ispolled over the ISDN ‘D’ channel;

FIG. 3 is a schematic of the system embodying the present invention;

FIG. 4 is a detailed schematic of an embodiment of equipment forimplementing the Customer Terminal of the system of FIG. 3;

FIG. 5 is a schematic providing additional details as to theimplementation of the Customer Terminal given in FIG. 4;

FIG. 6 is a detailed schematic of an embodiment of the network showingthe Agency Terminal interconnection to the broadband network and theAutomation System and the connection of the Burglar Alarm system to theCustomer Terminal;

FIG. 7 is a schematic of an embodiment of the Agency Terminal;

FIG. 8 is a schematic of an embodiment of the Automation System;

FIG. 9 is a schematic of an embodiment of the Registration Server;

FIG. 10 is an exemplary message flow diagram illustrating the operationof the system under different operating scenarios including polling,transporting of alarms messages and the loss of poll response messages;

FIG. 11 is an exemplary message flow diagram illustrating the operationof the system during Customer Terminal and Agency Terminal start upscenarios;

FIG. 12 shows the protocol stacks that may be used in ADSL based systemsembodying the invention;

FIG. 13 show the protocol stacks used in the wireless IP based systems(for example GPRS or 1×RTT) embodying the invention;

FIG. 14 shows the preferred poll and poll response message formats usedin the preferred embodiment;

FIG. 15 shows the preferred format of the alarm notification messagesfrom the Customer Terminal to the Agency Terminal and the format of theacknowledge message from the Agency Terminal to the Customer Terminalused in the preferred embodiment;

FIG. 16 shows the preferred embodiment of the invention detailing thecomponents required to provide video functionality;

FIG. 17 shows a functional illustration of the circular buffer used atthe Customer Terminal to capture video events.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

FIG. 3 shows a communications system including a broadband network (35),Customer Terminals (33), site monitoring equipment such as Burglar Alarmequipment (31), Agency Terminals (37, 38), Automation Systems (310) andRegistration Servers (312).

Customer Terminals (33) are generally located at customer sites and aregenerally connected using the Voice Frequency (VF) interface (32) to thetelephone land line connection of one or more Burglar Alarm systems(31), as for example in a residential apartment building. Other forms ofconnection (32) between the Customer Terminal (33) to Burglar Alarmsystems (31) are possible, including Serial Interfaces, generallycovered by RS.232 and RS.485, local area network, such as Ethernet andthe use of individual control lines for input and output. In the priorart, Burglar Alarm systems (31) use the telephone land line connectionto automatically announce to a remote monitoring centre such as asecurity company the triggering of one or more detectors that are usedto indicate an alarm condition. The alarm condition is converted to VFusing an industry standard format signal for transmission over thetelephone land line.

Each Customer Terminal (33) is connected to the broadband network usingone or more broadband connections (34), including but not limited to(HFC) coaxial cable, copper cable (two wire and/or four wire), opticalfibre, cellular telephony or wireless. Multiple connections to thebroadband network may be used to provide redundancy and path diversity.These connections provide an always-on virtual path between the CustomerTerminals (33) and Agency Terminals (37). In addition, they are capableof operating in parallel with the telephone land line.

One or more Customer Terminals (33) are generally associated with one ormore Agency Terminals (37) so that in the simplest configuration oneAgency Terminal (37) monitors one Customer Terminal (33). For greaterreliability, two or more Agency Terminals (37, 38) operating in N+1redundancy mode may be used to monitor one Customer Terminal. Generally,two or more Agency Terminals (37) operating in N+1 redundancy mode areused to monitor one or more Customer Terminals (33). The RegistrationServer (312) is one of the means used by the preferred embodiment tocarry out the association of Customer Terminals (33) to Agency Terminals(37). In this manner the broadband network may support one or moreindependent communications networks each associated with one or moresecurity monitoring companies.

The Agency Terminals (37) are generally located on site at the securitymonitoring company. As this communications network can be used forpurposes other than security, such as telemetry, health monitoring andso on, the Agency Terminal (37) may reside in the premises of theorganisation carrying out the remote monitoring, or remotely accessedthrough an interface to the Agency Terminal (37).

In the preferred embodiment the alarm or event messages generated by theBurglar Alarm system (31) that are automatically announced on the VoiceFrequency interface (32) using an industry standard format areintercepted by the Customer Terminal (33), which decodes theannouncement, converting it into a message format suitable fortransmission over the broadband network (35). In the preferredembodiment the messages are sent over the broadband network using theknown Internet Protocol (IP) using the known UDP (User Datagramprotocol) transport protocol, alternative embodiments using TCP as thetransport protocol are also possible. The encapsulated alarm or eventmessages are sent by the Customer Terminal (33) to the associated AgencyTerminals (37) over the one or more broadband connections (34) availableto said Customer Terminal (33).

Customer Terminals (33) generally monitor the Burglar Alarm system (31)they are connected to using a range of means, including by generatingand receiving test signals or by intercepting the automated alarmannouncement generated by the Burglar Alarm system (31) in response to atest alarm. Customer Terminals (33) report the failure of any testsequence or any other exception to their associated Agency Terminals(37) by sending out copies of the announcement message over one or morebroadband connections (34) available to said Customer Terminal (33).

Agency Terminals (37) connect into the broadband network (36) throughone of a number of possible connection means, including but not limitedto wireless, copper cable, optical fibre and coaxial cable. A connectionover a local area network is also possible, allowing other broadbandtraffic to share the connection.

Agency Terminals (37) are generally, but not exclusively deployed in anN+1 redundant configuration, where N≧1. Redundant operation is achievedthrough the broadband network, although local interconnectivity betweenAgency Terminals (37) using a local area network connection between theAgency Terminals (37) is also supported (FIG. 6 reference (66)).

The Agency Terminals (37) send poll request messages to their associatedCustomer Terminals (33) over the broadband network (FIG. 10 and FIG.14). The Customer Terminals (33) send poll response messages in responseto each poll request message. In the event that the Customer Terminal(33) has not responded to a predetermined number of poll requests fromthe Agency Terminal (37) in a specified time interval, the pollingAgency Terminal (37) notifies the Automation System (310) over a dataconnection for example, including serial RS.232 link and a local areanetwork connection (39).

As Customer Terminals (33) may be equipped with one or more connectionsinto the broadband network (35) over which the polling is conducted, theseverity of the loss of poll responses from a particular CustomerTerminal (33) depends on the number of broadband connections (34)available to said Customer Terminal (33).

Agency Terminals (37) poll their associated Customer Terminals (33) overthe broadband network (35). Each poll (FIG. 14) includes an unencryptedidentifier as well as information uniquely identifying the sendingAgency Terminal (37) and the destination Customer Terminal (33). Thepoll response from the Customer Terminal (33) includes an unencryptedidentifier determined by a method programmed into the Network Processor(FIG. 4 reference (45)) of the Customer Terminal (33). The AgencyTerminal (37) implements a complementary method to ensure that each pollresponse identifier matches the poll request identifier. The method usedat the Customer Terminal (33) and the Agency Terminal (37) to generatethe identifiers is agreed on as part of the Customer Terminal's (33)registration process (FIG. 11 reference (113)).

In one particular embodiment, on start up, each Agency Terminal (37)registers with the one or more Registration Servers (312) configured toprovide N+1 redundancy by sending the Registration Servers (312) (FIGS.9 and 11) its IP address and a range of customer Burglar Alarm (31)system identifiers. The Customer Terminals (33) are manufactured withthe hard-coded World-Wide-Web address of the Registration Servers (312).On start up and following service restoration after equipment, network(34, 35, 36) or Agency Terminal (37) outage the Customer Terminals (33)access the Registration Servers (312) to identify their associatedAgency Terminals (37).

When registering, eg, on initial installation or on reboot, CustomerTerminals (33) provide the Registration Server (312) their IP address,their unique hardware identifier, and information obtained from theBurglar Alarm (31), such as security company telephone number andsecurity account number which are obtained from the Burglar Alarmsystem's dial up information intercepted by the Customer Terminal (33).The Registration Server (312) uses this information to determine thedestination Agency Terminals (37), and sends the IP addresses of theassociated Agency Terminals (37) to the registering Customer Terminal(33) for use in sending alarm messages to the associated AgencyTerminals (37).

The Registration Server (312) and Agency Terminals (37) implementmethods that reduce the likelihood of unauthorised units masquerading asvalid Customer Terminals (33) or Agency Terminals (37) by for examplestoring the range of valid unique hardware identifiers which are used toconfirm the identity of the connecting unit.

Alternative embodiments that avoid the need for the Registration Server(312) through the use of for example IP VPNs are possible. In onealternative embodiment, the message route is set up as part of thecustomer account configuration by the Telephone Company or InternetService Provider, so that messages from Customer Terminals (33) arerouted by the network to the associated Agency Terminals (37) using aprivate implementation of the known Internet network and using knownDomain Name Service (DNS) as the end-to-end message routing schemeavoiding the need for specialised message processing equipment in thenetwork and eliminating the need for a Registration Server (312).

During normal operation, event and alarm messages generated by BurglarAlarm equipment (31) are sent by the Customer Terminals (33) over thebroadband network (35) to their associated Agency Terminals (37). TheAgency Terminals (37) implement message synchronisation schemes thatensure that only one message is sent on to the Automation System (310)(FIG. 10 reference (102)) avoiding the duplicate display of alarms whichcould confuse operators by generating display clutter.

The number of Agency Terminals (37) and Customer Terminals (33) shown inFIG. 3 are for the purposes of illustration only, in practice the numberof terminals that may be linked to the communications network arelimited only by the range of IP addresses available.

Agency Terminals (37) also send configuration and other messages toCustomer Terminals (33) including software down-load (FIG. 15).

FIG. 4 provides further detail of the components making up the preferredembodiment of the Customer Terminal supporting both ADSL (48) andwireless (49) connections into the broadband network. The Burglar AlarmEquipment (41) may be security industry standard equipment, generallyavailable with a digital dialler and using various security industryVoice Frequency (VF) telephony formats to transmit automatedannouncements. The Alarm Panel Interface block (43) is programmable toreceive and decode messages generated by the Burglar Alarm Equipment(41) and is capable of interpreting/decoding messages of differentformats. The decoded messages from the Burglar Alarm Equipment (41) areforwarded to the Network Processor block (45) for encoding, addressingand dispatch. The Alarm Panel Interface block (43) is also used fortesting the Burglar Alarm Equipment (41), and reporting anyirregularities such as equipment fault, equipment missing orunauthorised reprogramming.

The Line Interface block (44) connects the Customer Terminal to thetelephone land line (411) used to convey the ADSL signal and containsthe switching circuitry (FIG. 5) used to bypass the Alarm PanelInterface block (43) and to provide the Burglar Alarm Equipment (41)with direct connection to the telephone land line (411) to be used totransmit automated announcements to the security company and the like inthe event of a Customer Terminal failure.

In an ADSL implementation shown in FIG. 4, the POTS Splitter block (46)is used to separate out the high frequency ADSL signals from the lowfrequency POTS signals carried on the telephone land line (411). The lowfrequency POTS signal is conveyed to the in-premises telephone line(412) and the high frequency signals are conveyed to the ADSL modemblock (48).

The ADSL Modem block (48) terminates the ATM cells used to carry thebroadband IP data to/from the broadband network, and to forward the IPdata to the Network Processor block (45). The Network Processor block(45) examines the data for messages from the associated AgencyTerminals, such as poll, control, configuration and acknowledgmentmessages, which are terminated (see also FIG. 10). Other messagescarried on the broadband connection to the Customer Terminal such asmessages used when ‘surfing’ the Internet are passed on to the Ethernetblock (47) by the Network Processor block (45). The Network Processorblock (45) also ensures that messages from the Ethernet block (47)destined to the broadband network are not addressed to any of theassociated Agency Terminals.

Event and alarm messages received by the Alarm Panel Interface block(43) are converted in the Network Processor block (45) into the known IPmessage format suitable for transmission over a broadband network. Themessages are sent out simultaneously over all the equipped broadbandinterfaces including the ADSL (48) block and the Wireless (49) IP block,preferably implemented over a cellular network such as GSM (GPRS), CDMA(1×RTT) or 3G, to the associated Agency Terminals. The Agency Terminalssend acknowledgment messages to the Customer Terminal indicating thatthe alarm message has been received (see also FIG. 10).

The Network Processor block (45) identifies conditions local to theCustomer Terminal that need to be reported to the Agency Terminals. TheNetwork Processor block (45) generates messages corresponding to theseconditions using the known IP message format suitable for transmissionover a broadband network. The messages are sent out simultaneously overall the equipped broadband interfaces including the ADSL (48) block andthe Wireless (49) IP block, preferably implemented over a cellularnetwork such as GSM (GPRS) or CDMA (1×RTT), to the associated AgencyTerminals. The Agency Terminals send an acknowledgment message to theCustomer Terminal indicating that the alarm message has been received(see also FIG. 10).

The Power (410) block is used to power the Customer Terminal and chargea battery for the provision of power in the event of AC mains failure.

In the preferred embodiment, the Customer Terminal may operate using anADSL connection, using the in-built ADSL Modem (48) or using a wirelessIP connection with the in-built Wireless Modem (49) which supportsconnection into the broadband network in places where land lineconnection is not supported. For improved reliability Customer Terminalsmay operate using both an ADSL connection, using the in-built ADSL Modem(48) and using a wireless IP connection with the in-built Wireless Modem(49).

FIG. 5 details implementation of the voice frequency interface for theADSL embodiment which includes the ADSL and wireless mode of operation.The telephone land (51) line used to convey the ADSL and POTS signalenters the Customer Terminal unit through an ADSL low pass filter (52).The high frequency components are directed to an ADSL modem block (53).The low frequency components pass through a normally energised relay(55), shown in the unenergised state, and exit to the in-premisestelephone cabling (59). During normal operation, the telephone land lineinterface (58) of the Burglar Alarm Equipment is connected to theCustomer Terminal's VF Port (54) through a normally energised relay (56)shown in the unenergised state. In the event of the Customer Terminalfailing, or losing power, relays (55), (56) and (57) assume the statesshown in FIG. 5, providing the Burglar Alarm Equipment with a directconnection to the telephone land line (58 to 51). Table 1 shows theactive terminals for the relays in the powered state and in the powerloss state. Terminal 2 of relay 57 may be used to monitor the linefeeding signal provided to the Burglar Alarm equipment (510). Moresecure monitoring may be achieved by superimposing a signal, such as atone, on the line and monitoring the signal.

TABLE 1 Relay Operation Active Terminal Active Terminal RELAY PoweredPower Loss 55 2 1 56 2 1 57 2 1

FIG. 6 details the preferred embodiment of the Agency Terminalinterfaces. In the preferred embodiment, at least two collocated AgencyTerminals (64) are used operating in 1+1 redundancy, each connected tothe broadband network, one using an ADSL connection with a copper line(61) and an ADSL modem (63) and the other using a point to pointmicrowave connection (62) providing both redundancy and path diversity.Optionally, the Agency Terminals (64) are connected to a local areanetwork used for communications between Agency Terminals (64) forpurposes such as process monitoring and database synchronisation.Alternative embodiments using different means of connecting to thebroadband network are possible.

Agency Terminals (64) poll their associated Customer Terminals, thepolling process is coordinated to ensure that only one Agency Terminal(64) polls all the Customer Terminals that are associated with thesecurity company or the like. The non-polling Agency Terminals (64)monitor the polling Agency Terminal (64) by internal messages over theirmutual local area network (66) or broadband connection. When the pollingAgency Terminal (64) is found to be faulty, another associated AgencyTerminal (64) takes over the polling task. Alternative embodiments arepossible using dynamic load sharing between the Agency Terminals (64) inthe N+1 redundancy group so that all Agency Terminals (64) in the groupare involved in the polling process.

Event and alarm messages are sent by Customer Terminals to eachassociated Agency Terminal (64) over the broadband network connection(62, 63) for forwarding to the Automation System (67) (see also FIG. 8)for display to the security company operators. The Agency Terminals (64)maintain process synchronisation to ensure that event and alarm messagesare only sent once to the Automation System (67) over the interface (65)which may include a number of options, including a serial link or alocal area network. Agency Terminal (64) messages to the AutomationSystem (67) that are not acknowledged by the Automation System (67), arere-sent by another Agency Terminal (64) after a predefined time intervalhas elapsed. This scheme supports equipment redundancy while eliminatingunwanted message duplication.

The message formats used on the connection (65) between the AgencyTerminals (64) and the Automation System (67) are similar to those usedon the connection (610) between the prior art Dialler Receiver (69) andthe prior art Automation System (67), which facilitates the fall-backoperation mode of the system as described above whereby in the event ofa malfunction of a Customer Terminal the Burglar Alarm Equipment isprovided with a direct connection to the telephone land line and usesdial-up means through the public switched telephone network (68) to sendalarm announcement to the Dialler Receiver (69) used to provide theback-up means and thereby to the Automation System (67).

Item (612) shows the preferred embodiment of the system when using ADSLas the broadband access. The copper line from the telecommunicationsnetwork carries the signal for both the ADSL (621) and the telephony(622) services. The Customer Terminal (612) terminates the ADSL traffic.The ADSL signal is removed by filtering (46) and the reconstitutedtelephony signal made available to the telephone sets inside thecustomer's premises (623). A further advantage of this embodiment isthat the installation of the central splitter is significantlysimplified by having it located as part of the Customer terminal. TheBurglar Alarm equipment (611) is terminated on the Alarm Panel Interface(43) of the Customer Terminal.

From time to time the customer or the monitoring company (625) may wishto access the alarm panel directly through the PSTN (626). This isachieved by implementing in the Customer Terminal Line Interface (44) acontrol function responsive to a bypass command. In one embodiment aRing Detection capability is used allowing the customer to determineusing software functionality the conditions under which the CustomerTerminal (612) connects the Burglar Alarm equipment (611) directly tothe telephone line.

The following scenarios are included

-   -   1. The customer (625) rings twice. The first ring burst is        short, followed within 30 seconds by a longer ring burst which        results in the Burglar Alarm equipment (611) being connected to        the line by the Customer Terminal (612) to terminate the call    -   2. Distinctive ring, where the Customer Terminal (612) listens        for a particular ring cadence. Up on detecting that cadence it        connects the Burglar Alarm equipment (611) to the telephone line        allowing it to terminate the call

A further advantage of this arrangement is that the broadband trafficassociated with the security service is terminated inside the CustomerTerminal (612) and is not available on the local area network (631)eliminating the risk of unauthorised users (630) defeating the securitysystem.

FIG. 7 is a schematic of the preferred embodiment of the Agency Terminalimplemented by means of software executing on commercially availablecomputer equipment. In the preferred embodiment the database maintainsthe broadband IP addresses of all associated Customer Terminals as wellas their unique hardware identifier. The PollThread (71) is used totrigger the polling of the Customer Terminals and implements the methodfor generating the poll request message identifier and verifying thepoll response message identifier. The Agency Terminal also implementsthe method for decoding the alarm messages, converting the messages sentby the Customer Terminal over the broadband network into a formatsuitable for interfacing to the prior art Automation System. Thedatabase also provides the means for synchronisation between the two ormore Agency Terminals operating in N+1 redundancy.

FIG. 8 shows a possible embodiment of a known Automation System suitablefor use in a system embodying the present invention. The AutomationSystem maintains records in its database of the active customers of thesecurity company and the like and the alarm messages and theirsubsequent action for each customer. When an alarm message is receivedby the Automation System it displays the meaning of the message and theidentity of the affected customer on a suitable display means, andprovides the operator with means to determine the action to take, asagreed upon with the customer from time to time.

FIG. 9 shows the preferred embodiment of the Registration Server,implemented as a software program executing on standard commercialcomputer equipment. The Registration Server may be connected to thebroadband network using redundant means such as ADSL and wireless. Itmaintains records in its database of all active Agency Terminals andtheir identification codes and IP addresses. The Registration Serveralso maintains records in its database of all Customer Terminals andtheir identification codes and IP addresses. In addition, theRegistration Server implements a method that allows it to identifyCustomer Terminals and Agency Terminals as authorised or unauthorisedbased on their identification codes. Authorised Agency Terminals areregistered with the Registration Server, whereas unauthorised AgencyTerminals are reported to the network supervision group as agreed by therelevant industry association. Authorised Customer Terminals areregistered by the Registration Server and are provided with the IPaddresses of their associated Agency Terminals, while unauthorisedCustomer Terminals are rejected and their registration attempt reportedto the network supervision group.

As noted above, alternative embodiments that use IP VPNs with DNS arepossible that avoid the need for the Registration Server.

FIG. 10 is a message flow diagram used in the preferred embodiment.

The process used by Agency Terminals to poll their associated CustomerTerminals is illustrated by FIG. 10 (101) showing the message being sentout from the Agency Terminal (FIG. 7 functional block (71)) to theCustomer Terminal (FIG. 4 functional block (45)) and the response fromthe Customer Terminal (FIG. 4 functional block (45)) to the AgencyTerminal (FIG. 7 functional block (72)).

The messages associated with the delivery of an announcement messagefrom the Burglar Alarm system through the communication system to theAutomation System are illustrated by FIG. 10 (102). The eventannouncement is sent by the Burglar Alarm system to the CustomerTerminal (FIG. 4 functional blocks (41) and (43)). The Customer Terminalre-formats the message for transmission over the broadband network usingdata packets such as UDP packets over IP (FIG. 4 functional block (45))and forwards it to its associated Agency Terminals (74). The AgencyTerminals (74) verify the source of the alarm message using the uniqueidentifying information carried in the message and store the decodedalarm messages in their database (77), re-code the messages into theAutomation System protocol and forward the messages to the AutomationSystem (FIG. 7 functional blocks (74), (75) and (73)). Simultaneously,the Agency Terminals (74) return acknowledgment messages to the CustomerTerminal (FIG. 4 functional block (45)). The Customer Terminal thenacknowledges the alarm message to the Burglar Alarm system (FIG. 4functional block (43)). The Automation System (FIG. 8) acknowledges thereception of the alarm message to the specific Agency Terminal that hadsent the message to the Automation System. The Agency Terminal storesthe acknowledgment message in the common database (FIG. 7 functionalblock (77)). The Automation System then displays the message and maytrigger an audible alert to notify the system operators that a new alarmhas been received.

FIG. 10 item (103) illustrates the process associated with the CustomerTerminal (FIG. 4 functional block (43)) polling the Burglar Alarmsystem. The Customer Terminal triggers an alarm test and checks for theresponse. A correct response to such a test is terminated by theCustomer Terminal, while a missing response (not shown) is reported tothe Agency Terminal in a manner similar to the reporting of an eventfrom the alarm system.

FIG. 10 item (104) details the polling process used by the AutomationSystem to confirm the presence of the Agency Terminal (FIG. 7 functionalblock (73)).

FIG. 10 item (105) shows the messaging process involved with missedpolls from the Agency Terminal to the Customer Terminal. In thisprocess, the Agency Terminal (FIG. 7 functional block (71)) polls theCustomer Terminal (FIG. 4 functional block (45)) every T-seconds. TheAgency Terminal expects the Customer Terminal to response to a pollrequest in under t-seconds where t<T. If the response is not received inunder t-seconds, the Agency Terminal (FIG. 7 functional block (72))assumes that the response has been lost and re-polls the CustomerTerminal (FIG. 4 functional block (45)) a predetermined number of times,after which if no response has been received, an alarm is sent to theAutomation System. This process ensures that the loss or malfunction ofany Customer Terminal is identified within the polling interval.

FIG. 11 illustrates the communication system messages associated withthe Registration Server.

FIG. 11 item (111) shows the messages that result when an AgencyTerminal is added to the communications network. The Agency Terminal(FIG. 7 functional block (76)) registers with the Registration Server(FIG. 9 functional block (91)), in the process the Registration Serverreceives and stores the IP address of the registering Agency Terminal.The Registration Server returns an acknowledgment message to the AgencyTerminal indicating that the registration process has been successfullycompleted.

FIG. 11 item (112) describes the messages that are sent to theRegistration Server when a Customer Terminal is started up. The CustomerTerminal (FIG. 4 functional block (45)) uses various means including forexample its unique hardware identifier to identify itself to theRegistration Server (FIG. 9 functional block (92)), and providesinformation identifying the destination security company by, forexample, providing the telephone number that the Burglar Alarm systemdials and the Burglar Alarm system's preprogrammed account number. TheRegistration Server validates the identity of the Customer Terminal andreturns the IP address of each of the associated Agency Terminals. TheseIP addresses are used by the Customer Terminal to communicate directlywith the Agency Terminals.

FIG. 11 item (113) shows the message flow following the registrationprocess. Once registered, the Customer Terminal (FIG. 4 functional block(45)) connects to the Agency Terminal (FIG. 7 functional block (76))using the IP address it has obtained from the Registration Server (FIG.9 functional block (92)). The Agency Terminal then proceeds to configure(FIG. 7 functional block (76)) the Customer Terminal. Only after theAgency Terminal has completed the configuration of the Customer Terminaland has received the “acknowledge” message from the Customer Terminaldoes the Agency Terminal start to poll it.

FIG. 12 details the protocol stacks used in the embodiment of theinvention that uses ADSL as the connection means to the broadbandnetwork from the Customer Terminal. Item (121) shows the protocol stackimplementation in the Burglar Alarm system (prior art). Automatedannouncements from the Burglar Alarm system are sent in known formatsusing voice frequency signals to be sent out over the telephone landline connection.

The Burglar Alarm communications stack (121) includes

-   -   1. Event Message generator which converts the various alarm        reports to a string of digits    -   2. VF Format which converts the string of digits into VF tones    -   3. Analogue two-wire interface which applies the tone to the        telephone line

The Customer Terminal (FIG. 4 functional block (43)) implements aprotocol stack (122) that is complementary to that in the Burglar AlarmSystem. This protocol stack (122) is used by the Customer Terminal todecode the messages from the Burglar Alarm System. The decoded messagesare re-coded by the Customer Terminal (FIG. 4 functional block (45))protocol stack (123) for transmission over the broadband network. Themessage structure used is shown in FIG. 15 and is carried as a UDPmessage using the existing Internet Protocol (IP) which carries thesource and destination addresses for the messages.

The Customer Terminal protocol stack (122) includes

-   -   1. Analogue two-wire interface, this interface simulates the        PSTN to the Burglar Alarm equipment and behaves like a dialler        capture unit to receive the VF signals from the Burglar Alarm        equipment    -   2. VF Format, this block receives and detects the VF tones used        by the Burglar Alarm equipment to communicate    -   3. Event Message, this block reconstructs the original message        sent by the Burglar Alarm equipment

The Customer Terminal protocol stack (123) includes

-   -   1. Event Message block, this block assembles the event message        to be transmitted to the Agency Terminal    -   2. UTP, this block generates the proprietary message by affixing        header and trailer data to the event message    -   3. UDP, this block encapsulates the proprietary UTP message in        the known UDP format    -   4. IP, this block encapsulates the UDP message in the known IP        format    -   5. ATM, this block encapsulates the IP message in the known ATM        format    -   6. ADSL, this block encapsulates the ATM message in the known        ADSL format

FIG. 12 item (124) is the protocol stack used at the Agency Terminal(FIG. 7 functional block (74)) to decode the messages from the CustomerTerminal (FIG. 4 functional block (45)). The decoded messages are putthrough the Agency Terminal (FIG. 7 functional block (73)) protocolstack (125) for delivery to the Automation System for operator display.The reception of the event message by the Agency Terminal from theCustomer Terminal is acknowledged by the Agency Terminal to the sendingCustomer Terminal by the Agency terminal sending the acknowledge messageshown in FIG. 15.

The Agency Terminal protocol stack (124) includes

-   -   1. IP, this block un-encapsulates the UDP message    -   2. UDP, this block un-encapsulates the proprietary UTP message    -   3. UTP, this block un-encapsulates the Event Message included in        the proprietary UDP message    -   4. Event Message, this block re-creates the original Event        Message as sent by the Burglar Alarm equipment (121)

The Agency Terminal protocol stack (125) includes

-   -   1. AS Protocol, this block converts the Event Messages into a        string recognisable by the known Automation System    -   2. RS.232, this block transfers the message string to the known        Automation System using the known RS.232 serial communications        format

The contents of the alarm/event messages and their correspondingacknowledgment messages are encrypted for added security.

FIG. 14 shows the message format used for poll requests and pollresponses. Poll requests are sent by the Agency Terminal (FIG. 7functional block (71)) as UDP messages using the Internet Protocol,which includes the source and destination addresses of the message. Thepoll request is terminated on the Customer Terminal (FIG. 4 functionalblock (45)) which responds by sending the poll response message shown inFIG. 14, also sent as a UDP message using the Internet Protocol, whichincludes the source and destination addresses of the message. The pollresponse message is terminated by the Agency Terminal (FIG. 7 functionalblock (72)) that has sent the poll request.

FIG. 13 details the protocol stacks used in the embodiment of theinvention that uses IP-based cellular telephony means such as GPRS or1×RTT as the connection means to the broadband network from the CustomerTerminal. The message path is similar to that outlined above for ADSL.

FIG. 16 details the preferred embodiment of the invention for thecarriage of video signals for the use of remote alarm verification andarchiving.

As shown in FIG. 16, a number of cameras (1603), are connected to theCustomer Terminal (1603), to which the Alarm System (1602) is connected.The Customer Terminal (1603) connects into a data network (1604) toAgency Terminal (1605), which in turn connects to the Automation System(1606) and Video Server (1607). Automation System (1606) and VideoServer (1607) may be linked by communication link (1608). Customer(1610) may be provided with secure access to the Video Server (1607)which may be provided, for example, over the Internet (1609).

The Burglar Alarm Equipment (1601) generates automatic alarmannouncements that are received by the Customer Terminal (1602). Themessage from the Burglar Alarm Equipment (1601) identifies the type ofalarm and the originating zone to the Customer Terminal (1602). TheCustomer Terminal (1602) is configured with a mapping between the VideoCameras (1603) and the alarm zones.

The Video Cameras (1603) are connected to the Customer Terminal using aknown connection system such as USB or local area network (LAN).

The images generated by the Video Cameras (1603) are continuouslycaptured and stored by the Customer Terminal Network Processor (FIG. 4Item (45)) in individual circular buffers 1701 (FIG. 17) ofpre-determined length. Each Video Camera (1603) is allocated a uniquecircular buffer 1701. When an event occurs in a zone that corresponds toa particular Video Camera (1603) (or any zone), a pointer is used toidentify the corresponding video frame in the circular bufferdesignating Frame 01 (FIG. 17 Item ‘E’). Another pointer designatingFrame p (FIG. 17 Item ‘S’) is used to identify the last position in thecircular buffer which is not to be over-written. The third pointerdesignating Frame m (FIG. 17 Item ‘F’) is the next position in thecircular buffer to which a video frame is to be written. Pointer ‘F’ maybe thought of as moving clock-wise as it fills the buffer, that is itindexes from Frame 01 to Frame p. Once pointer ‘F’ reaches pointer ‘S’,that is, the next frame to be written is Frame p, the recording stops.This method allows for images of activities leading up to the alarm tobe stored as well as images of events following the alarm.

In a preferred embodiment, when the camera receives an event signal fromits associated detector, the camera records one or more frames at ahigher resolution and possibly switching from black and white to colourto improve the clarity of the corresponding images.

The Customer Terminal (1602) forwards the message from the Burglar AlarmEquipment (1601) to the Agency Terminal (1605) via the Data Network(1604) as described above.

The Agency Terminal (1605) forwards the message to the Automation System(1606). Concurrently the Agency Terminal (1605) uses the message typeand the originator to identify the alarm as having associated videoinformation (FIG. 7 Item (77)). The Agency Terminal (1605) commands theCustomer Terminal (1602) to send the video information stored in thecircular buffer 1701 (FIG. 17). The received video data is time-stampedand stored on the Video Server (1607) its location noted in the AgencyTerminal (1605) database (FIG. 7 Item (77)).

The video information on the Video Server (1607) can be accessed by theSecurity Company operator using a specialised application executing onthe Automation System (1606) over link 1608. In addition, at theSecurity Companies discretion, the customer (1610) may access the VideoServer (1607) directly through the Internet (1609) via a secure web siteand view the stored images on a known web browser using known plug-ins.

Following the up-loading of the data from the circular buffer (FIG. 17),the Video Camera (1603) continues recording images in the circularbuffer. These can be up-loaded to the Video Server (1607) on commandfrom the Agency Terminal (1605).

Video recording may be locally disabled by the customer when disarmingthe Burglar Alarm Equipment (1601), which results in an ‘opening’message being sent when the customer is present on the premises, andautomatically enabled when the Burglar Alarm Equipment (1601) is armedsending a ‘closing’ message to the Automation System (1660).

1. A telemetry system including: one or more supervision terminals; oneor more remote terminals associated with at least one of the one or moresupervision terminals; a data network linking the one or moresupervision terminals and the one or more remote terminals via analways-on connection through the data network via a path between the oneor more supervision terminals and the one or more remote terminals;wherein; the one or more supervision terminals is in communication withone or more corresponding associated remote terminals across the datanetwork using network facilities of the data network for carriage andswitching or routing of messages; wherein messages from the one or moreremote terminals to the one or more supervision terminals aretransmitted across the network, the message content being passedtransparently across the network between the one or more remoteterminals to the one or more supervision terminals; wherein the one ormore supervision terminals monitor the integrity of the path between theone or more remote terminals according to a fixed or programmableroutine; and wherein the one or more supervision terminals monitor pollresponses from the one or more remote terminals to determine pathintegrity.
 2. A telemetry system as claimed in claim 1, including one ormore monitoring devices connected to one or more remote terminals,wherein the one or more remote terminals monitor the one or moremonitoring devices and report the condition and/or status of the one ormore monitoring devices to the one or more supervision terminals.
 3. Asystem as claimed in claim 1, wherein the one or more remote terminalsare linked to the network via an ADSL link and/or a wireless link.
 4. Asystem as claimed in claim 1, wherein the one or more supervisionterminals incorporate, or are connected to an associated monitor system,the monitor system being adapted to make information received from theone or more supervision terminals available to an operator, wherein theone or more supervision terminals include monitor interface emulationmeans converting information from the one or more supervision terminalsto the monitor information format.
 5. A system as claimed in claim 1,wherein the one or more supervision terminals and/or the one or moreremote terminals include supervision terminal self-diagnostic meansand/or remote terminal self-diagnostic means respectively, and sendsupervision terminal status reports or remote terminal status reportsrespectively to the associated monitoring system.
 6. A system as claimedin claim 1, including an association register recording the associationbetween one or more remote terminals and one or more supervisionterminals, the association register being accessible to the one or moresupervision terminals, wherein the one or more supervision terminals andthe one or more remote terminals have access to the association registervia the data network.
 7. A system as claimed in claim 1, including oneor more image capture devices linked to the one or more remoteterminals, and a memory associated with the one or more image capturedevices, the memory recording a moving time window of images from theimage capture device.
 8. A system as claimed in claim 7, including oneor more associated detectors, wherein an image capture command from anyof said detectors freezes the moving time window in the memory tocapture a series of images in a specific time interval.
 9. A system asclaimed in claim 8, wherein at least some post-image capture commandimages are stored in a further buffer.
 10. One or more supervisionterminals for use in a system as claimed in claim 1, including: asupervision terminal network interface means adapted to respond to analert condition originating from one or more remote terminals, monitorsystem interface adapted to transmit an alert message to an associatedmonitor system and to receive a first acknowledgment message therefrom,the supervision terminal network interface being adapted to transmit asecond acknowledgment signal to the one or more remote terminals fromwhich the alert condition originated, the one or more supervisionterminals including a poll request generator to transmit poll requeststo the one or more remote terminals, the one or more supervisionterminals including a poll response processor to monitor the pollresponses received from the one or more remote terminals to monitor theintegrity of the path between the one or more supervision terminals andthe one or more remote terminals, the one or more supervision terminalsincluding a message receiver to receive messages from the one or moreremote terminals which have been transmitted across the network withoutprocessing of the message content at an intermediate point in thenetwork.
 11. One or more supervision terminals for use in a system asclaimed in claim 1, the one or more supervision terminals including:path integrity monitoring means adapted to monitor the integrity of thepath between the one or more supervision terminals and one or moreremote terminals by transmitting poll requests to the one or more remoteterminals and monitoring the poll response from the one or more remoteterminals to verify the integrity of the path between the one or moresupervision terminals and the one or more remote terminals, wherein theone or more supervision terminals are adapted to receive messages fromthe one or more remote terminals the message content of which has beentransmitted transparently across the network through the intermediatenodes in the network.
 12. One or more supervision terminals as claimedin claim 11, including: a supervision terminal network interface; alertcondition storage means; alert condition processing means; a monitorsystem interface including: message means transmitting an alertcondition originating from the one or more remote terminals to themonitor system; means for receiving and storing of a firstacknowledgment message sent by the monitoring system.
 13. One or moreremote terminals for use in a system as claimed in claim 1, including aremote terminal network interface means adapted to: receive and respondto poll requests from one or more associated supervision terminals;transmit alert condition to one or more associated supervisionterminals; monitoring device interface adapted to receive monitoringmessages originating from the associated monitoring device and totransmit third acknowledgement messages to the monitoring device;wherein the one or more remote terminals are adapted to receive messagesfrom the one or more supervision terminals the message content of themessages being transmitted transparently across the network through theintermediate nodes in the network.
 14. One or more remote terminals asclaimed in claim 13, including: a bypass switch; and remote terminalmonitor means monitoring the one or more remote terminals, the remoteterminal monitor means being adapted to operate the bypass switch todisconnect the one or more remote terminals and to connect an associatedmonitoring device to a telephone network in the event of a failure ofthe one or more remote terminals.
 15. One or more remote terminals asclaimed in claim 13, wherein the address of one or more associationregisters is recorded in the one or more terminals to enable the one ormore terminals to communicate with the registration server.
 16. One ormore remote terminals as claimed in claim 13, including one or moreimage capture devices linked to the one or more remote terminals, theone or more image capture devices being associated with one or moreassociated detectors to capture images of a designated area on receiptof an image capture command from an associate detector.
 17. One or moreremote terminals as claimed in claim 16, wherein the one or more imagecapture devices is associated with a first corresponding associatedcircular buffer capable of recording a predetermined amount of imageinformation into which the one or more image capture devices continuallystore image information, and wherein, on receipt of an image capturecommand, the one or more remote terminals cause the storing of imageinformation into the first circular buffer to cease after apredetermined amount of image information is stored in the firstcircular buffer, leaving a predetermined amount of pre-image capturecommand information remaining in the buffer.
 18. A system as claimed inclaim 16, wherein at least some post-image capture command images arestored in a further buffer.
 19. A method of transmitting information ina telemetry system including: one or more supervision terminals; one ormore remote terminals associated with the at least one or moresupervision terminals; a data network linking the one or moresupervision terminals and the one or more remote terminals via analways-on connection through the data network; the method including thesteps of: monitoring the one or more remote terminals from at least oneof the one or more associated supervisions terminals via the datanetwork using the network facilities for carriage and switching orrouting of messages; transmitting messages from the one or more remoteterminals to the one or more supervision terminals across the network,the message content being passed transparently across the networkbetween the one or more remote terminals to the one or more supervisionterminals; and monitoring the path integrity between the one or moresupervision terminals to the one or more remote terminals bytransmitting poll requests from the one or more supervision terminals tothe one or more remote terminals and monitoring poll responses from theone or more remote terminals according to a fixed or programmableroutine; and wherein the one or more supervision terminals monitors pollresponses from the one or more remote terminals.
 20. A method as claimedin claim 19, wherein the one or more remote terminals transmitassociation information to an association register.
 21. A method asclaimed in claim 19, wherein the one or more remote terminals retrieveinformation from the associated monitoring device for transmission tothe association register.
 22. A method as claimed in claim 19, includingcompiling a registration table associating the one or more remoteterminals with the one or more associated supervision terminals.
 23. Amethod as claimed in claim 22, including installing the address of theregistration table in the one or more remote terminals, the one or moreremote terminals being programmed to communicate with the registrationtable on start up of the one or more remote terminals.